Half-duplex data communication systems are undesirable because of the inherent delay which exists between the transmission and reception of data. While delay can be reduced from the round-trip delay which occurs in "ping-pong" type half-duplex systems, it comes at the cost of some system complexity. Existing full-duplex data communication systems utilize techniques such as frequency division multiplexing which requires the use of expensive system components such as modems, multiplexers, demultiplexers, filters, etc. Full-duplex optical data links (ODL) utilize techniques such as wave division multiplexing which require specialized devices such as optical couplers, splitters, wavelength routers, etc. In certain full-duplex data communication system applications, such as providing broadband data services to the home over existing cable facilities or new optical fibers, the cost is a critical factor in the provisioning of these data services.
What is needed is a simple and low-cost full-duplex data communication technique that can be utilized over cable and/or optical fiber systems.